• The Journal of the Korea Contents Association
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• v.14 no.3
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• pp.259-268
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• 2014

The purpose of this study is to investigate correlation between experience of visiting the dentist and oral symptoms with 10,701 high school seniors in the research data of the 8th juvenile online health behavior carried out in 2012. The results of this research showed that the lower academic grades, the more tooth crack they experienced, and the lower economic conditions, the more toothache they tended to experience. The main reasons they visited the dentist were because their teeth ached, tingled or throbbed with pain. Scores of oral symptoms, sex, economic conditions and the number of experience of visiting the dentist were found to have a significant correlation. In order to improve high school students' dental health continually, we need to install the school dental health room and need to systemize continuous dental health care system for high school students, along with development of various school dental health education programs, by vitalizing prevention based school dental health education.

• Korean Journal of Ichthyology
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• v.9 no.1
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• pp.99-107
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• 1997

The early life history and reproductive ecology of Siniperca scherzeri were studied to obtain fundamental information in aquaculture and reinforcement of natural population in Soyang Lake, Buk-myon, Chunchon-shi, Kangwon-do from June to October 1996. Symptric species with adult fishes (+1 ages) of Siniperca scherzeri were 11 species belonging to 6 families and 10 genera and those with Juveniles (2~3 months) were 5 species belonging to 4 families and 5 genera. The sex radio of this species were 1 (female, 85) : 1.24 (male, 105). Adult and juvenile of this species were predominantly piscivores. Bluegill, Lepomis macrochirus, Zacco platypus, common carp, Cyprinus carpio, unidentified fish and shrimp were important components of the food items. The spherical eggs were demersal and separative without a colorless transparent chorion and slightly yellowish yolk containing one large oil globule (0.5~0.7mm). The egg just after fertilization were measuring 1.72~2.05mm (n=30), and expanded to 2.27~2.58mm (n=30) in diameter after 30 min. Hatching occurred 130~155 hrs after fertilization at water temperature of $20{\sim}25^{\circ}C$ and newly hatched larvae measuring 5.5~7.1mm in total length. In the newly hatched larvae, numerous branched malanophores were distributed on the yolk and abdomen of caudal peduncle. In ten-day old larvae, the yolk was mostly absorbed and the head spines and the teeth were well developed. All fin rays were formed and total length of the larvae were reached 13.6~15.6mm at 20 days after hatching. In fifty-five day old larvae were similar in both body shape and color to adult. The juvenile stage at 4 months after hatching were attained 86.4~95.3mm (n=7) in total length and 8.77~14.78g (n=7) in body weight.